Process and apparatus for making hydrochloric acid.



A. ENGELSTAD'.

PROCESS AND APPARATUS FOR MAKING HYQROCHLORIO ACID,

APPLICATION FILED FEBA,1914.

' Patented Dec. 22, 1914.

fizz/971 507":

a sufficient quantity of hydrogen to insure- Y um'rnn s'mans mam-r1orrion;

ALE IEENGELSTAD, 0E BERLIN, HAMPSHIR'E' PROCESS AND- APPARATUS FOR,MAKING HYDROGHLORIC ACID.

tion and burning of two streams of the. gases in a-suitable combustionchamber, in

which the combustion is sustained. or supported by the combustion of oneor more other gases. For, example, according to my process, I mayconstantly supplyv to the combustion chamber chlorin and-oxygen atordinary or atmospherictemperatures, and

the simultaneous combustion of the oxygen and of the chlorin, one in thepresence of the other. The water vapor, resulting from the combustion ofthe hydrogen and the,

oxygen,-may be condensed and employed'for absorbing hydrochloric acidproduced by the other reaction, additional water, if necessary, beingsupplied from an outside source for the absorption of the remainingacid.

Instead of supplyingmerely enough hydro:

gen for the *quantitive reactions with the chlorin and the oxygen, 1preferably supply a constant large excess of hydrogen for reducing thetemperature in thecombustion chamber. It is evident that I may supply tothe combustion chamber the three gases in substantially pure form,regulating the supply of each of them to secure the optimum results.According to modern methods, however, in many plants, electrolytic cellsare employed for themanufacture of caustic soda with the production of.chlorin and hydrogen as by-products;

h In such plants, as a practical" matter, it is unnecessary to securethe gases in an absolutely-pure state, more or less water vapor being.delivered with the chlorin and with the hydrogen, and a relatively largeproportion of air finding its way into the chlorin ducts, particularlywhen the chlorinand the hydrogen are removed from the cells by' suction.My process, therefore, provides a method for commercially makinghydrochloric acid even when there are relatively Specification ofLetters Patent.

Patented Dec. 22 1914.

I Application filed February}, 1914. Serial No; 816,457.

large quantities ofair and water vapor mixed with the chlorin.

()n the accompanying drawings, I have illustrated moreor lessconventionally apparatus which may be utilized in carrying out myprocess. I

. 9n the drawings, I have indicated at 1, 2,

3 and 4 a-plurality of electrolytic cells such as. are utilized in thedecomposition. of a solution of sodium chlorin for the manufacture ofchlorin and caustic soda. I have illustrated only four of these cells,but it will be understood that a large-number mavbe utilized. From thecellindicated at 1, 22s chlorin is drawn by suction through the ndult 5,there being "like conduits at 5 leadingfrom the other cells 4, 3 and 2to a manifold 7 which delivers the chlorin for use the. manufacture ofbleach or other materlal's. From all of the cells indicated,

conduits 9 are provided for supplying the hydrogen evolvedin the cathodecham;

bers to a manifold 8; The chlorin and the hydrogen supplied by the cellsare conducted to a combustion chamber 12, the hydrogen being conductedthereto from the manifold 8 by a; conduit 13 having a water-seal 14:,and the chlorin being conducted thereto from the conduit 5 ,by a conduit15: provided with a water-seal 16. It will be observed that the chlorinand hydrogen from the cells are supplied in the proportion of 1 to 4;the hydrogen being greatly in excess of that required for the productionof hydrochloric acid. The combustion chamber 12 fconsists preferably ofan elongated narrow box made of fire-brick,-

quartz' or other suitable fire-proof material, and having a removablecover of like material. 'l he conduit 15 for the chlorin terminates ina;quartz nozz-leprojecting a short distance into the combustioncham- "her,and the conduit 13 for the hydrogen terminates in a like nozzle which isshown as projecting into the side of the combustion chamber. Projectingdownwardly into the combustion chamber into the cover are one or morespark plugs such as are used in-the ignition oi the fuel in a'gas orgaso- 'lene engine. These spark plugs are located relatively near. thenozzles and are connected; 1n an electric circuit so that electricsparksmaybe formed in the atmosphere of the gases in the combustion-'chainber. Preferably' the spark plugs: are removable so that, afterthe combustion in the chamber I has been started and continued for sometime, they may be removed and the apertures filled with plugs of anysuitable ma-' terial.

It will be observed that in the chlorin duct 15 there is formed an inlet17 for the entrance of air (or oxygen from a suitable source) into theduct. This inlet is provided with a valve 18 by which the amount of airdrawn into the duct may be regulated to vary the proportions of thechlorin and air delivered to the combustion chamber. T permit theentrance of sufficient air to supply oxygen for reaction with thehydrogen in the combustion chamber to produce an oxyhydrogen flame bywhich to support and maintain the combustion of the chlorin andhydrogen, as will be subsequently explained; Leading from the end of thecombustion chamber, there is an eduction duct or conduit 19 for theproducts of combustion, including water vapor, and hydrochloric acid,and such inert gases, as nitrogen, as may be present. This conduit isconnected with a condensing coil 20 over which water is permitted todrip for initially reducing the temperature of the products ofcombustion. Said coil in turn is connected with an earthenware coil 21submerged in a tank 22 through which water is constantly flowing, forthe condensation of. the water vapor formed by the combination of theoxygen and hydrogen. The delivery end of the coil 21 is connected to aninclined pipe or conduit 23 midway between the ends thereof. The lowerend of the conduit or pipe 23 is submerged in a tank 24 containingwater. The upper end of the conduit 23 is connected to the lower end ofthe tower 25. Within the tower is placed any inert material such asquartz or coke, and through it trickles water delivered to the towerfrom a pipe 26 at the upper end thereof. Leading also from the top ofthe tower is an eduction conduit 27 with which is connected an ex,-haust pump 28. a

The streams of mixed chlorin and air (nitrogen and oxygen) and ofhydrogen are delivered into the combustion chamber with the hydrogenpreferably in excess. An electric current is passed through the coilscausing the formation of a series of sparks. Thereupon the hydrogen andthe oxygen, which have a greater affinity than hydrogen and chlorin, arefirst ignited and burn with a steady flame. Suflicient hydrogen,however, is present for reaction with the chlorin also, and thecombustion of the chlorin and hydrogen takes place, being supported andmaintained by the combustion of the hydrogen and oxygen. Thehydrochloric acid and the water va or, which are formed by the reactionsin t e combustion chamber, are drawn therefrom by the ex-- haust fanthrough the condensing coils, the

thereth r ough and is absorbed thereby, the acidulated water flowingdownward through the pipe into the tank 2a, the pipe being large enoughand the supply of water being so'regulated that the pipe is never filledbut always permits the passage of the hydrochloric acid into the,tank24:.

Because of the high temperatures in the combustion chamber, due to theexothermic reactions which take place therein, it is necessary to usematerial for constructing the combustion chamber and the eduction ductleading therefrom, capable of withstanding high heat. lltherefore, aspreviously stated, prefer to form the combustion chamber of fire-brickor other like material. It is desirable, however, to use quartz in theformation of the conduits for the hydrochloric acid resulting from thecombustion. l Dhe degree, however, to which quartzunay be heated withoutcrumbling is limited and it is highly desirable, therefore, that somemeans be provided for reducing the temperature in the combustionchamber. This I accomplish in the present case by admitting nitrogenWith the oxygen into the combustion chamber, and by providing a largeexcess of hydrogen necessary for the reaction with the oxygen andchlorin- V In lieu of having a direct inlet into the chlorin duct forthe entrance of air or oxygen therein, T find, in actual practice, thatthis is not necessary, becauseof leaky connections between thecombustion chamber.

and the cells from which the chlorin is drawn. This varies of course inactual practice, but I find that, under normal conditions, with cellsused in the manufacture of caustic soda and bleach, the gas deliveredthrough the conduit 15 to the combustion chamber, even though the airinlet 18 is closed, will consist approximately of 40% chlorin and air,though these proportions constantly vary from one cause or another.Inaddition to the air, the gas entering' through the chlorin duct hasmixed with it a. trace of moisture, but this does not interfere with thecombustion, either of the oxygen or of thechlorin. A

I It will'be observed that I haveprovided a gasometer 1.0 for thereception and storage of a supplyof hydrogen, and that thisgasometercommunicates with the conduit 13 \by a valved conduit 110. This is donein order that I may always have an excess supply of hydrogen for" thesteady combustion of the oxygen in the combustion chamber, should thecells 1 to 4: inclusive be temporarily shut down. .It is not necessary,of course. that the hydrogen and the chlorin should be drawn from thesame battery of cells; in fact, I find it convenient to draw. theisupplyof hydrogen from one set of cells and to draw the chlorin from a"difierent set, but in any case the cells are so connected as to supplyan excess of the hydrogen. Hence, in the event that it benecessary toshut down either set of cells, it does not cause the cessation of theflame in the combustion chamber, since, by opening the air inlet and thevalve in the conduit 110, a free supply of air is admitted to thechlorin duct, and

the combustion of the oxygen in the atmosphere of hydrogen in thecombustion chamber continues without intermission. If the cellssupplying hydrogen be temporarily shutdown, a sufficient supply ofhydrogen is furnished from the asometer.

The exhaustfan at the top of the tower maintains a vacuum of about oneand onehalf (1%) inches of water, and insures the drawing of thechlorin, air, and oxygen into the combustion chamber, and the passage ofthe unabsorbed hydrochloric acid into the tower for absorption by thewater delivered thereto.

As will be seen from the foregoing, it is unnecessary to preheat any ofthe gases prior to their delivery to the combustion chamber. and that,after the combustion is once started, itwill continue withoutinterruption even if the supply'o'f chlorin be shut off from time totime.- Preferably a current is maintained in the spark-plug circuit forsome time until the combustion is well started and is continuing evenly.I

In the event that itbe desired to make repairs in those portions of theapparatus beyond the combustion chamber, in which event the continuedformation of hydrochloric acid would be objectionable on account of thefumes escaping into the air. the supply of chlorin may be cut off, andair and hydrogen fed into the said chamber, and the combustion of oxygenand hydrogen continued without any material reduction in the radiantheat of the walls of said chamber.

\Vhat I claim is 1. The herein described process of manu-- facturinghydrochloric acid, which consists in continuously supplying streams ofl1ydrogenroxygen and chlorin into contact-with each other. and burningthe hydrogen and chlorin and the hydrogen andoxygen simultaneously. andconducting away continu-. ously and recovering the hydrochloric acid andwatervapor produced by such combustion.

2. The herein described process of manugen and'oxygen, and conductingaway and recovering the water vapor and the hydrochloric acid producedby such combustion.

3. The herein described process of manufacturing hydrochloric acid,which consists in supplying streams of chlorin,oxygen and hydrogen intoa combustion chamber, burning in saidchamber the hydrogenand chlo-- rin,supporting and maintaining such coinbustion by burning in said chamberhydrogen and oxygen, conducting away the water vapor and the lydrochloric acid produced by said combustion, condensing the water vapor,absorbing hydrochloric acid therein, and recovering the acidulatedproduct of. condensation.

i. Thejherein described process of manufacturing hydrochloric acid,which consists in continuously supplying oxygen, chlorin and hydrogen,burning said chlorin and a portion of said hydrogen and simultaneouslyburning said oxygen and another por-. tion of said hydrogen all in acommon chamber, regulating the supply of hydrogen to provide an excessthereof over that needed for said reactions, for reducing thetemperature in the combustion chamber, and

continuously "conducting away and recovering the'products of combustion.

5. The herein described process of manufacturing. hydrochloric acid.which consists in supplying a stream of chlorin and fair,

supplying a stream of hydrog'en, simultaneously burning the chlorin,oxygen and hys drogen in a common chamber, conducting away thehydrochloric acid-and water vapor produced by such combustion,condensing the water vapor, absorbing a portion of the said hydrochloricacid by the condensed water. absorbing the remaining hydromg a. streamof hydrogen and a stream of chloric acid by water from a separate Afirst-mentioned stream and hydrogen of the second-mentioned stream insaid chamber, conducting away nitrogen and the hydrochloric acid andwater vapo produced by such combustion, and recoveri ng the hydrochloricacid.

8. The herein. escribed process of making hydrochloric acid-whichconsists in supply ing a stream of hydrogen and a stream of mixed airand chlorin to a chamber, simultaneously burning oxygen and chlorin of pthe first-mentioned stream and hydrogen or the second-mentioned streamin said chamber, conducting away nitrogen and the hydrochloric acid andwater vapor produced by such combustion, condensing-the water vapor andabsorbing a portion of the hydrochloric acid therein, and recovering theremaining hydrochloric acid.

9. ihe herein described process of manufacturing hydrochloric acid,which consists in continuously supplying oxygen and" an excess ofhydrogen into a combustion chambe'r, continuously burning the oxygen anda gen to a' chamber, igniting the chlorin and hydrogen and temporarilymaintaining their series of electric combustion by forming a mixed airand chlorin to a chamber, simultaneously burning oxygen and chlorin ofthe sparks in the presence of the mixed gases,

and withdrawing and recovering the hydrochloric acid produced by suchcombustion.

11. An apparatus for the manufacture of hydrochloric acid comprisingseparate sources of chlorin-and hydrogen, a combustion chamber, meansfor supplying streams of chlorin and hydrogen thereto from said sources,an electric circuit including one or more spark plugs projecting intothe combustion chamber for igniting and temporarily maintaining thecombustion of the said gases,'and means for withdrawing and recoveringthe hydrochloric acid.

12. An apparatus for the manufacture of hydrochloric acid, comprising acombustion chamber, ducts for supplying streams of air, chlorin andhydrogen to said combustion chamber, means for conducting awayhydrochloric acid and water vapor produced by the combustion in saidchamber, and means for condensing the water vapor in the presence ofsaid hydrochloric acid.

13. An apparatus for manufacturing hydrochloric acid, which comprises acombustion chamber, a duct for supplying hydrogen thereto, a ductforsupplying mixed air and chlorin to said chamber, an inclined conduit towhich the products of combustion are delivered, a recovery tank withwhich the lower end of said conduit communicates, and an absorbing towercommunicating with the other end' of said conduit.

In testimony whereof l have affixed my signature, in presence of twowitnesses.

- v ALF ENGELSTAD. TWitnesses I MARC-Us B. Mar, P. W. PEzzET'rI.

